In a simple LP or HP RC filter, is there a scenario where the centering frequency can fluctuate? So say the filter is a low pass and its set to pass everything up to 800hz, is there a situation where it may cut off at 750hz, or perhaps at a different time cut off at 825hz, etc.?
Maybe the guitarist picks the strings harder/softer, air pressure, ambient temperature, etc. could cause this? I am researching simulation techniques and trying to understand if factors like these could make an amp model a little more realistic in terms of tonal quality and dynamics.
The "Feel" of an amp plays a major role in defining the characteristics of how one plays and changing frequencies that are allowed to pass into a non-linear function will alter the feel quite drastically (at least in the digital amp sim world). The difference could be relatively small too, 120hz changed to 100hz will add a more "saturated" type feel. You may not notice much difference in tone, but you will in "feel". In the analog world I have noticed this "difference" in cut off only added to tone(allowed for more bass), but had little effect on feel.
So, can (or do) RC Filter cut off frequencies fluctuate?